diff --git a/CRM/Core/Payment/PayPalImpl.php b/CRM/Core/Payment/PayPalImpl.php
index 3fde78c1bbfd..99c25654651d 100644
--- a/CRM/Core/Payment/PayPalImpl.php
+++ b/CRM/Core/Payment/PayPalImpl.php
@@ -39,6 +39,10 @@
 class CRM_Core_Payment_PayPalImpl extends CRM_Core_Payment {
   const CHARSET = 'iso-8859-1';
 
+  const PAYPAL_PRO = 'PayPal';
+  const PAYPAL_STANDARD = 'PayPal_Standard';
+  const PAYPAL_EXPRESS = 'PayPal_Express';
+
   protected $_mode = NULL;
 
   /**
@@ -50,21 +54,50 @@ class CRM_Core_Payment_PayPalImpl extends CRM_Core_Payment {
    * @param CRM_Core_Payment $paymentProcessor
    *
    * @return \CRM_Core_Payment_PayPalImpl
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   public function __construct($mode, &$paymentProcessor) {
     $this->_mode = $mode;
     $this->_paymentProcessor = $paymentProcessor;
-    $this->_processorName = ts('PayPal Pro');
-    $paymentProcessorType = CRM_Core_PseudoConstant::paymentProcessorType(FALSE, NULL, 'name');
 
-    if ($this->_paymentProcessor['payment_processor_type_id'] == CRM_Utils_Array::key('PayPal_Standard', $paymentProcessorType)) {
+    if ($this->isPayPalType($this::PAYPAL_STANDARD)) {
       $this->_processorName = ts('PayPal Standard');
-      return;
     }
-    elseif ($this->_paymentProcessor['payment_processor_type_id'] == CRM_Utils_Array::key('PayPal_Express', $paymentProcessorType)) {
+    elseif ($this->isPayPalType($this::PAYPAL_EXPRESS)) {
       $this->_processorName = ts('PayPal Express');
     }
+    elseif ($this->isPayPalType($this::PAYPAL_PRO)) {
+      $this->_processorName = ts('PayPal Pro');
+    }
+    else {
+      throw new PaymentProcessorException('CRM_Core_Payment_PayPalImpl: Payment processor type is not defined!');
+    }
+  }
 
+  /**
+   * Helper function to check which payment processor type is being used.
+   *
+   * @param $typeName
+   *
+   * @return bool
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
+   */
+  public function isPayPalType($typeName) {
+    // Historically payment_processor_type may have been set to the name of the processor but newer versions of CiviCRM use the id set in payment_processor_type_id
+    if (empty($this->_paymentProcessor['payment_processor_type_id']) && empty($this->_paymentProcessor['payment_processor_type'])) {
+      // We need one of them to be set!
+      throw new PaymentProcessorException('CRM_Core_Payment_PayPalImpl: Payment processor type is not defined!');
+    }
+    if (empty($this->_paymentProcessor['payment_processor_type_id']) && !empty($this->_paymentProcessor['payment_processor_type'])) {
+      // Handle legacy case where payment_processor_type was set, but payment_processor_type_id was not.
+      $this->_paymentProcessor['payment_processor_type_id']
+        = CRM_Core_PseudoConstant::getKey('CRM_Financial_BAO_PaymentProcessor', 'payment_processor_type_id', $this->_paymentProcessor['payment_processor_type']);
+    }
+    if ((int) $this->_paymentProcessor['payment_processor_type_id'] ===
+      CRM_Core_PseudoConstant::getKey('CRM_Financial_BAO_PaymentProcessor', 'payment_processor_type_id', $typeName)) {
+      return TRUE;
+    }
+    return FALSE;
   }
 
   /**
@@ -74,6 +107,7 @@ public function __construct($mode, &$paymentProcessor) {
    * with someone else's login.
    *
    * @return bool
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   protected function supportsBackOffice() {
     if ($this->_processorName == ts('PayPal Pro')) {
@@ -92,6 +126,7 @@ protected function supportsBackOffice() {
    * 'notify' flow a key difference is that in the notify flow they don't have to return but in this flow they do.
    *
    * @return bool
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   protected function supportsPreApproval() {
     if ($this->_processorName == ts('PayPal Express') || $this->_processorName == ts('PayPal Pro')) {
@@ -107,6 +142,7 @@ protected function supportsPreApproval() {
    *
    * @return bool
    *   Should form building stop at this point?
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   public function buildForm(&$form) {
     if ($this->supportsPreApproval()) {
@@ -186,6 +222,8 @@ protected function supportsRecurContributionsForPledges() {
    *
    * @param array $values
    * @param array $errors
+   *
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   public function validatePaymentInstrument($values, &$errors) {
     if ($this->_paymentProcessor['payment_processor_type'] == 'PayPal' && !$this->isPaypalExpress($values)) {
@@ -251,6 +289,7 @@ protected function setExpressCheckOut(&$params) {
    * @param array $storedDetails
    *
    * @return array
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   public function getPreApprovalDetails($storedDetails) {
     return empty($storedDetails['token']) ? array() : $this->getExpressCheckoutDetails($storedDetails['token']);
@@ -266,6 +305,7 @@ public function getPreApprovalDetails($storedDetails) {
    *
    * @return array
    *   the result in an nice formatted array (or an error object)
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   public function getExpressCheckoutDetails($token) {
     $args = array();
@@ -362,9 +402,13 @@ public function doExpressCheckout(&$params) {
   /**
    * Create recurring payments.
    *
+   * Use a pre-authorisation token to activate a recurring payment profile
+   * https://developer.paypal.com/docs/classic/api/merchant/CreateRecurringPaymentsProfile_API_Operation_NVP/
+   *
    * @param array $params
    *
    * @return mixed
+   * @throws \Exception
    */
   public function createRecurringPayments(&$params) {
     $args = array();
@@ -481,6 +525,7 @@ public function doPayment(&$params, $component = 'contribute') {
    * @param string $component
    * @return array
    *   the result in an nice formatted array (or an error object)
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   public function doDirectPayment(&$params, $component = 'contribute') {
     $args = array();
@@ -538,7 +583,7 @@ public function doDirectPayment(&$params, $component = 'contribute') {
 
     $result = $this->invokeAPI($args);
 
-    //WAG
+    // WAG
     if (is_a($result, 'CRM_Core_Error')) {
       return $result;
     }
@@ -597,8 +642,9 @@ public function doQuery($params) {
   /**
    * This function checks to see if we have the right config values.
    *
-   * @return string
+   * @return null|string
    *   the error message if any
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   public function checkConfig() {
     $error = array();
@@ -627,6 +673,7 @@ public function checkConfig() {
 
   /**
    * @return null|string
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   public function cancelSubscriptionURL() {
     if ($this->_paymentProcessor['payment_processor_type'] == 'PayPal_Standard') {
@@ -737,6 +784,7 @@ static public function handlePaymentNotification() {
    * @param array $params
    *
    * @return array|bool|object
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   public function updateSubscriptionBillingInfo(&$message = '', $params = array()) {
     if ($this->_paymentProcessor['payment_processor_type'] == 'PayPal') {
@@ -807,6 +855,7 @@ public function changeSubscriptionAmount(&$message = '', $params = array()) {
    * @return array
    *   - pre_approval_parameters (this will be stored on the calling form & available later)
    *   - redirect_url (if set the browser will be redirected to this.
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   public function doPreApproval(&$params) {
     if (!$this->isPaypalExpress($params)) {
@@ -1125,6 +1174,7 @@ protected function mapPaypalParamsToCivicrmParams($fieldMap, $paypalParams) {
    * @param array $params
    *
    * @return bool
+   * @throws \Civi\Payment\Exception\PaymentProcessorException
    */
   protected function isPaypalExpress($params) {
     if ($this->_processorName == ts('PayPal Express')) {